Just like Jeanne I do two to three passes on a certification exam. But I don't calculate a time limit for each question
When I struggle too long with a question, I mark it for review and continue with the next one. I try to hold on to a certain pace (depending on number of questions and exam duration).After the 1st round I start again at the beginning (the 1st question). During this iteration I verify the questions I already answered in the 1st round and I answer all flagged questions.If time permits and I'm still not fed up , I take another quick pass through of all questions. I only make a change, if I'm 100% convinced my current answer is wrong.
I took the OCAJP7 exam at the beginning of this month. I tried to keep a pace of 1 minute per question during my 1st iteration. I needed 65 minutes for 70 questions, so mission accomplished. I believe I flagged at most 10 questions which got all answered during the 2nd iteration. I still had 15-20 minutes left, but it was the last day of my vacation, so no 3rd iteration
When
I took the SCJP6 a few years ago, I did 3 iterations and I even changed an answer in the 3rd iteration of a very tricky question.
I'm not from New York City, but I think Jeanne's disclaimer applies to me as well. Although I needed more time for my school tests and exams